5
The top of the integrator has a solid cover that can be used when monitoring the dark
background. We have found it convenient to leave one holding screw loosely in
place and simply rotate the cover to monitor dark and light signals, see Figure 2.2.
Figure 2.2
: Closed and open detector assembly, as used in Model SPR-01
It is important that you do not allow dust or other materials to fall inside the detector
head; this would invalidate the calibration provided by Luzchem.
The bottom of the detector head has a threaded hole (1//4-20 threads) that can be used
for mounting the detector. A very thin aluminum plate protects the PTFE
compartment from damage by objects inserted through the mounting hole. The
maximum penetration is 3 mm. Do not force screws to penetrate more than this, since
they can damage the integrator compartment.
2.2.
Spectrometer
The heart of Luzchem spectroradiometers is a 2048 element spectrometer contained
in the control module. It covers a minimum range of 230 to 860 nm and has optical
components to optimize ultraviolet detection. Data points are acquired about every
~0.3 nm; however the software converts the data so that points are displayed at 1 nm
intervals.
The spectrometer is quite robust and ideal for field work and wherever portability is
important. However, it should be protected for water and high temperatures.
Stray light is quite low, for example: < 0.05% at 600 nm, < 0.10% at 435 nm, and <
0.10% at 250 nm. The grating used has 600 lines/mm and has been blazed at 400 nm.
Spectrometer control is achieved via the USB port; no other source of power is
required to operate the spectrometer.
2.3.
Fiber optic cable
The fiber optic cable, connecting the spectrometer to the detector head is an integral
part of your instrument (it is fully enclosed in the spectroradiometer model SPR-02),
and instrument calibration is dependent on the fiber used.